Japanese Patent No. 2990646 discloses that a cured article having excellent heat resistance, chemical resistance, solvent resistance, releasability, water repellency, oil repellency, weatherability, and the like can be produced from a composition comprising a straight chain perfluoropolyether compound having at least 2 alkenyl groups per molecule and having perfluoropolyether structure in its backbone; an organosilicon compound having at least 2 hydrogen atoms bonded to the silicon atom per molecule; and a hydrosilylation catalyst. The polymer described in Japanese Patent No. 2990646 which has the terminal structure of [an aromatic ring-Si atom-vinyl group] has high curing speed since it has [Si atom-vinyl group] structure. However, the moiety wherein an aromatic ring is bonded to the Si atom is known to contribute for reducing the acid resistance. On the other hand, a polymer having no [an aromatic ring-Si atom-vinyl group] structure on its terminal (for example, a polymer having the terminal structure of [an aromatic ring-an alkylene group-vinyl group] and a polymer having the terminal structure of [amide group having an aromatic ring substituent on its side chain-alkylene group-vinyl group]) had excellent acid resistance while such polymer had the drawback of inferior curing speed.
The compositions as described above had the performance sufficient for almost all applications. However, further improvement in acid resistance is desirable for use in an environment where the cured article is brought in contact with a strong acid, for example, in the case of sealants used in a chemical plant. Higher curing speed is also important in view of molding efficiency.